TWI598644B - Polarizing film manufacturing method - Google Patents

Description

Polarized film manufacturing method Field of invention

The present invention relates to a method of producing a polarizing film. The polarizing film obtained by the production method can be formed into an optical film by a single layer or a liquid crystal display device (LCD), an organic EL display device, an image display device such as a CRT or a PDP.

Background of the invention

In terms of watches, mobile phones, PDAs, notebook computers, screens for personal computers, DVD players, TVs, etc., liquid crystal display devices are rapidly expanding the market. In the liquid crystal display device, the polarization state is visualized by switching of the liquid crystal, and the polarizer is used because of the display principle. In particular, in applications such as TV, more enhanced high luminance, high contrast, and wide viewing angle are required, and in the polarizing film, higher transmittance, high polarization, high color reproducibility, and the like are required.

As the polarizing member, since it has high transmittance and high degree of polarization, it is most commonly used, for example, an iodine-based polarizing member which is a structure in which iodine is adsorbed to polyvinyl alcohol and extended. The mechanical strength of such a polarizer is extremely weak, and there is a disadvantage that the polarizer can be significantly lowered due to shrinkage by heat or moisture. because Thus, the obtained polarizer is directly bonded to the transparent protective film coated with the adhesive via an adhesive, and used as a polarizing film.

It has also been proposed to improve the adhesion strength between the polarizer and the transparent protective film. Therefore, after the surface of the polarizer having the adhesive layer is subjected to activation treatment, the polarizer and the transparent protective film are bonded to each other to manufacture. Polarized film (Patent Document 1). In general, since the polarizer is made of a hydrophilic polymer film such as a polyvinyl alcohol-based film, the polarizer has a certain moisture content. Patent Document 1 describes that the water content of the polarizer is preferably 20% by weight or less, preferably 0 to 17% by weight, and more preferably 1 to 16% by weight.

Prior technical literature Patent literature

Patent Document 1: Japanese Laid-Open Patent Publication No. 2009-008860.

Summary of invention

Since the polarizer has been transported through the guide roller, since the water content of the polarizer exceeds 11% by weight, there is no problem in transportability even when it is brought into contact with the guide roller for transport. In recent years, polarizers having a water content of 11% by weight or less have been produced. However, when the moisture content of the polarizer is less than 11% by weight, the holding force between the guide roller and the guide roller for conveying the polarizing member becomes high, and the conveyance property may be poor, or may be followed by a transparent protective film. There was a bad fit in the fit. In particular, in the case where the surface of the polarizer is conveyed while being in contact with the guide roller, the conveyance is carried out. Sexuality is prone to bad occurrences.

An object of the present invention is to provide a method for producing a polarizing film which is provided with a transparent protective film on at least one surface of a polarizer via an adhesive layer.

In order to solve the above problems, the inventors of the present invention have been working hard to develop the following method, and have found the following method for producing a polarizing film.

That is, the present invention relates to a method for producing a polarizing film which is provided with a transparent protective film on at least one side of a polarizer via an adhesive layer, and the method for producing the polarizing film is characterized by having the following Step: Step (1): by applying an activation treatment to at least one surface of the polarizing member having a water content of 11% by weight or less, the surface roughness (Ra) of the surface of the polarizer is 0.6 nm or more; Step (2): The polarizing member to which the activating treatment has been applied is transported while contacting the surface of the activated polarizing member with the guide roller; and step (3): applying an adhesive to the polarizing member that is transported via the guide roller to form the aforementioned The surface of the layer of the agent layer and/or the surface of the transparent protective film forming the adhesive layer; and the step (4): bonding the polarizer and the transparent protective film to each other via the adhesive.

The method for producing the polarizing film described above can be suitably applied to a case where the thickness of the polarizing member is 10 μm or less.

The method for producing a polarizing film described above can be suitably applied to the case where the polarizing member is composed of a polyvinyl alcohol-based resin having a dichroic substance oriented. The strip-shaped polarizing film is obtained by extending the layered body including the polyvinyl alcohol-based resin layer formed on the thermoplastic resin substrate by a two-stage extending step of extending in the air and extending in the boric acid water. By.

In the method for producing a polarizing film, corona treatment or plasma treatment may be employed as the activation treatment.

In the method for producing a polarizing film, the activation treatment by the activation treatment is corona treatment, and the discharge amount during the corona treatment is preferably 250 to 1000 W/m ² /min.

In the method for producing a polarizing film of the present invention, a low water content polarizing member having a water content of 11% by weight or less is used, and the surface of the polarizing member is contacted before the polarizing member and the transparent protective film are bonded by an adhesive. The roller is transported on one side. On the other hand, in the method for producing a polarizing film of the present invention, the surface of the polarizer contacting the guide roller is subjected to an activation treatment before the surface of the polarizer contacts the guide roller to control the surface roughness (Ra) of the polarizer. Above 0.6 nm. It is known that when the polarizer having a surface roughness (Ra) of 0.6 nm or more is controlled as described above, even when the polarizer having a low water content is brought into contact with the guide roller, the conveyance can be favorably performed. As a result, the bonding of the subsequent polarizer and the transparent protective film via the adhesive is improved, and the polarizing film can be efficiently produced.

P‧‧‧ polarizer

T1, T2‧‧‧ transparent protective film

A1, A2‧‧‧ adhesive

F1‧‧‧Single-sided protective polarizing film

F2‧‧‧Double-sided protective polarizing film

C‧‧‧Activation treatment device

D‧‧‧ Coating device

R1‧‧‧Processing roller

R2‧‧‧ coating roller

R3, R4‧‧‧ laminating rolls

G1, G2‧‧‧ guide roller

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic view showing an example of an embodiment of a method for producing a polarizing film of the present invention.

Detailed description of the preferred embodiment Form for implementing the invention

Hereinafter, a method of producing the polarizing film of the present invention will be described. The polarizing film of the present invention is provided on at least one surface of the polarizing member, and a transparent protective film is provided via the adhesive layer. The polarizing film of the present invention is obtained by sequentially applying the steps (1) to (4). Steps (1) to (4) will be described below with reference to Fig. 1 . In FIG. 1, the steps (1) to (4) are applied to the one-side protective polarizing film F1 to produce a double-sided protective polarizing film F2, and the one-side protective polarizing film F1 is attached to the one side of the polarizing member P. The adhesive layer A1 is provided with a transparent protective film T1.

<Step (1)>

In the step (1), the surface roughness (Ra) of the surface of the polarizer is set to 0.6 nm or more by applying an activation treatment to at least one surface of the polarizer having a water content of 11% by weight or less. Fig. 1 is a treatment roller R1, and the surface of the polarizer P of the one-side-protected polarizing film F1 is activated by an activation treatment device C.

<polarizer>

The polarizing member is not particularly limited, and various substances can be used. The polarizing material may, for example, be a saponification in which a dichroic substance such as iodine or a dichroic dye is adsorbed on a polyvinyl alcohol-based film, a partially dimethylacetalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer. A hydrophilic polymer film such as a film, which is uniaxially stretched, and a polyolefin-based oriented film such as a dehydrated material of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among them, a polarizing member comprising a polyvinyl alcohol-based film and a dichroic material such as iodine is preferred. The thickness of the polarizers is not particularly limited and is usually about 1 to 80 μm. Thickness of polarizer The degree is preferably 30 μm or less, preferably 20 μm or less, more preferably 10 μm or less.

A polarizing material obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be prepared by, for example, immersing polyvinyl alcohol in an aqueous solution of iodine to dye and extending it to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride or the like. Further, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed with water. By washing the polyvinyl alcohol-based film with water, the surface of the polyvinyl alcohol-based film can be washed with dirt or an anti-caking agent, and the polyvinyl alcohol-based film can be swollen to avoid unevenness such as uneven dyeing defects. Effect. The extension system may be carried out after dyeing with iodine, or may be extended while dyeing, or may be dyed with iodine after stretching. It can also be extended in an aqueous solution or a water bath such as boric acid or potassium iodide.

<<Thin polarizer>>

A thin polarizing member having a thickness of 10 μm or less can be used as the polarizing member. From the viewpoint of thinning, the thickness is preferably from 1 to 7 μm. Such a thin polarizer has a small thickness unevenness defect, is excellent in visibility, and has a small dimensional change, so that durability is good, and it is also suitable for reducing the thickness of the polarizing film.

Typical examples of the thin polarizing member include, for example, Japanese Patent Laid-Open No. Sho 51-069644, JP-A-2000-338329, WO2010/100917, and PCT/JP2010/001460, or the like. A thin polarizing film described in the specification of Japanese Patent Publication No. 2010-263692, and the like. The thin polarizing film can be obtained by a process comprising the steps of: a polyvinyl alcohol resin (hereinafter also referred to as The step of extending the PVA-based resin layer and the resin substrate for stretching in a state of being laminated, and the dyeing step. According to this production method, even if the PVA-based resin layer is thin, it can be extended without any defects such as cracking due to elongation, supported by the resin substrate for stretching.

As the thin polarizing film, in the method including the step of stretching in the state of the laminated body and the dyeing step, the polarizing performance can be improved at a high magnification, and the specification is disclosed in WO2010/100917, PCT/JP2010/001460, or the like. Japanese Patent Application No. 2010-269002, and the specification of Japanese Patent Application No. 2010-263692, etc., which are included in the method of extending the aqueous solution of boric acid, are preferably obtained, especially in the specification of Japanese Patent Application No. 2010-269002 or It is preferred that the method described in the specification of 2010-263692 is obtained, which comprises the step of assisting aerial extension before extending in an aqueous solution of boric acid.

The thin high-performance polarizing film described in the specification of the above-mentioned PCT/JP2010/001460 is a thin high-function having a thickness of 7 μm or less composed of a PVA-based resin which is formed on a resin substrate and has a dichroic material oriented. The polarizing film has an optical property of a monomer transmittance of 42.0% or more and a degree of polarization of 99.95% or more.

The thin high-performance polarizing film can be produced by forming a PVA-based resin layer by coating and drying a PVA-based resin on a resin substrate having a thickness of at least 20 μm; and impregnating the formed PVA-based resin layer. In the dyeing solution of the dichroic substance, the dichroic substance is adsorbed to the PVA-based resin layer; and in the aqueous boric acid solution, the PVA-based resin layer to which the dichroic substance is adsorbed is extended together with the resin substrate to increase the total stretching ratio. Become 5 times the original length on.

Further, in the method for producing a laminate film comprising a thin high-performance polarizing film for orienting a dichroic substance, the thin high-performance polarizing film can be produced by the following steps: a step of producing a laminated film, the laminated body The film includes a resin substrate having a thickness of at least 20 μm and a PVA-based resin layer formed by coating and drying an aqueous solution containing a PVA-based resin on one surface of the resin substrate; and the adsorption step includes The laminated film of the resin substrate and the PVA-based resin layer formed on one surface of the resin substrate is immersed in the dyeing liquid containing the dichroic substance, thereby adsorbing the dichroic substance to the PVA contained in the laminated film. a resin layer; in the extending step, the laminate film containing the PVA-based resin layer having the dichroic substance adsorbed thereon is stretched in an aqueous solution of boric acid so that the total stretching ratio is 5 times or more of the original length; a step of laminating a thin film of a thin high-performance polarizing film by stretching a PVA-based resin layer having a dichroic substance and a resin substrate together on one side of the resin substrate The thin high-performance polarizing film is a polarizing film having a thickness of 7 μm or less composed of a PVA-based resin layer having a dichroic material oriented, and has a monomer transmittance of 42.0% or more and polarized light. Optical characteristics of 99.95% or more.

In the present invention, as the polarizing member having a thickness of 10 μm or less, a continuous strip-shaped polarizing film composed of a PVA-based resin having a dichroic substance oriented may be used, which is composed of two segments consisting of an air-assisted extension and an extension of boric acid water. The stretching step is carried out by extending a laminate including a polyvinyl alcohol-based resin layer formed on a thermoplastic resin substrate. The thermoplastic resin substrate is preferably a non-crystalline ester-based thermoplastic resin substrate or a crystalline ester-based heat. A plastic resin substrate.

The thin polarizing film of the above-mentioned Japanese Patent Application No. 2010-269002 and the Japanese Patent Application No. 2010-263692 is a continuous strip-shaped polarizing film composed of a PVA-based resin having a dichroic material. The layered body including the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is stretched in a two-stage extending step of extending in the air and extending in boric acid water to form a thickness of 10 μm or less. . The thin polarizing film is preferably formed to have the following optical characteristics: when the monomer transmittance is T and the degree of polarization is P, P>-(10 ^0.929T-42.4 -1)×100 is satisfied (at T<42.3). B), and conditions for P≧99.9 (under T≧42.3).

Specifically, the thin polarizing film can be produced by the following method for producing a thin polarizing film, comprising: a step of forming an extended intermediate product, that is, by film-forming a continuous ribbon-shaped amorphous ester heat The PVA-based resin layer on the plastic resin substrate is extended in the air at a high temperature to form an extended intermediate product composed of the oriented PVA-based resin layer; and the step of producing the colored intermediate product, that is, by the extension intermediate product Adsorption of a coloring substance to form a colored intermediate product composed of a PVA-based resin layer having a dichroic substance (preferably a mixture of iodine or iodine and an organic dye); and a step of forming a polarizing film, that is, by The colored intermediate product is stretched in boric acid water to form a polarizing film having a thickness of 10 μm or less composed of a PVA-based resin layer having a dichroic substance oriented.

In the production method, the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate by stretching in the air at a high temperature and extending in boric acid water preferably has a total stretching ratio of 5 or more. Boron for extending in boric acid water The liquid temperature of the aqueous acid solution can be 60 ° C or higher. It is preferable to apply an insolubilization treatment to the colored intermediate product before extending the colored intermediate product in the aqueous boric acid solution. In this case, it is preferred to carry out the immersion of the colored intermediate product in a boric acid aqueous solution having a liquid temperature of not more than 40 °C. The amorphous ester-based thermoplastic resin substrate can be used as a copolymerized polyethylene terephthalate containing copolymerized polyethylene terephthalate copolymerized with isophthalic acid and copolymerized with cyclohexane dimethanol. An ester, or other amorphous polyethylene terephthalate copolymerized with polyethylene terephthalate, and preferably composed of a transparent resin, the thickness of which may be the thickness of the film-formed PVA-based resin layer. More than 7 times. Further, the stretching ratio in the air high temperature extension is preferably 3.5 times or less, and the stretching temperature in the air high temperature extension is preferably a glass transition temperature of the PVA resin or more, specifically, a range of 95 ° C to 150 ° C. When the high-temperature extension in the air is carried out by uniaxial stretching at the free end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more and 7.5 times or less. In the case where the high-temperature extension in the air is carried out by uniaxial stretching at the fixed end, the total stretching ratio of the PVA-based resin layer formed on the amorphous ester-based thermoplastic resin substrate is preferably 5 times or more and 8.5 times. the following.

More specifically, a thin polarizing film can be produced by the method described below.

A continuous belt-shaped substrate of an isophthalic acid copolymerized polyethylene terephthalate (amorphous PET) copolymerized with 6 mol% of isophthalic acid was produced. The glass transition temperature of the amorphous PET was 75 °C. A layered body composed of an amorphous PET substrate and a polyvinyl alcohol (PVA) layer in a continuous strip shape was produced in the following manner. Incidentally, the glass transition temperature of the PVA is 80 °C.

Prepare 200μm thick amorphous PET substrate and 4~5% concentration In the PVA aqueous solution, the PVA powder having a polymerization degree of 1,000 or more and a saponification degree of 99% or more is dissolved in water. Next, a PVA aqueous solution was applied onto a 200 μm-thick amorphous PET substrate, and dried at a temperature of 50 to 60° C. to obtain a laminate having a 7 μm-thick PVA layer formed on an amorphous PET substrate.

A laminate having a 7 μm thick PVA layer was subjected to the following steps including a two-stage extension step of aerial assisted extension and boric acid water extension to produce a thin high-performance polarizing film of 3 μm thick. According to the air-assisted extension step of the first stage, the laminate including the 7 μm thick PVA layer was extended together with the amorphous PET substrate to form an extended laminate including a 5 μm thick PVA layer. Specifically, the extended laminated body is a laminate having a 7 μm thick PVA layer placed on an extension device equipped with an oven set at an extension temperature of 130 ° C, and is uniaxially stretched at a free end so that the stretching ratio is 1.8 times. Founder. By this stretching treatment, the PVA layer contained in the extended laminated body was changed into a 5 μm thick PVA layer in which PVA molecules were oriented.

Next, in the dyeing step, a colored layered body obtained by adsorbing iodine on a PVA layer having a 5 μm thick orientation of PVA molecules was formed. Specifically, the colored layered body is obtained by immersing the laminated body in a dyeing liquid containing iodine and potassium iodide at a liquid temperature of 30 ° C to form a monomer permeability of the PVA layer constituting the finally formed high functional polarizing film. 40 to 44% of the method is immersed for any time, and iodine is adsorbed to the PVA layer contained in the extended laminate. In this step, the dyeing liquid is water as a solvent, and the iodine concentration is in the range of 0.12 to 0.30% by weight, and the potassium iodide concentration is in the range of 0.7 to 2.1% by weight. The concentration ratio of iodine to potassium iodide is 1 to 7. Incidentally, potassium iodide is required to dissolve iodine in water. In more detail, by immersing the extended laminated body in a dyeing liquid having an iodine concentration of 0.30% by weight and a potassium iodide concentration of 2.1% by weight for 60 seconds, iodine is adsorbed to the PVA molecule. A colored layered body of oriented 5 μm thick PVA layer.

Next, the colored layered product was further extended together with the amorphous PET substrate by the step of extending the boric acid water in the second stage to form an optical thin film layered body comprising a PVA layer of a high functional polarizing film of 3 μm thick. Specifically, the optical film laminate is formed by placing a colored laminate on an extension device equipped with a processing device and uniaxially extending at a free end so as to have a stretching ratio of 3.3 times, wherein the processing device is provided with boric acid and A boric acid aqueous solution having potassium iodide and a liquid temperature ranging from 60 to 85 °C. In more detail, the liquid temperature of the aqueous boric acid solution was 65 °C. Further, the boric acid content was 4 parts by weight with respect to 100 parts by weight of water, and the potassium iodide content was 5 parts by weight with respect to 100 parts by weight of water. In this step, the colored layer body having the adjusted iodine adsorption amount is first immersed in the boric acid aqueous solution for 5 to 10 seconds. . Thereafter, the colored layered body was uniaxially stretched at a free end for 30 to 90 seconds by a multi-array roller having a peripheral speed which was provided as an extension means of the processing apparatus so that the stretching ratio was 3.3 times. Through the stretching treatment, the PVA layer contained in the colored layered product was changed into a 3 μm-thick PVA layer in which the adsorbed iodine became a polyiodide complex and was highly oriented in the same direction. This PVA layer constitutes a high-performance polarizing film which constitutes an optical film laminate.

Although it is not a necessary step in the manufacture of the optical film laminate, it is preferable to take out the optical film laminate from the aqueous boric acid solution by a washing step, and to form a 3 μm-thick PVA layer on the amorphous PET substrate. The attached boric acid is washed with an aqueous solution of potassium iodide. Thereafter, the washed optical film laminate was dried by a drying step using a warm air of 60 °C. Further, the washing step is a step of eliminating appearance defects such as precipitation of boric acid.

It is also not a necessary step in the manufacture of optical film laminates. However, the 80 μm-thick cellulose triacetate film may be bonded to the surface of the 3 μm-thick PVA layer formed on the amorphous PET substrate by a bonding and/or transfer step. The amorphous PET substrate was then peeled off, and a 3 μm thick PVA layer was transferred onto a 80 μm thick cellulose triacetate film.

[other steps]

The method for producing the above-mentioned thin polarizing film may include other steps in addition to the above steps. Other steps include, for example, an insolubilization step, a crosslinking step, a drying (adjustment of moisture content) step, and the like. Other steps can be performed at any suitable point in time.

The insolubilization step is typically carried out by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing insolubilization treatment. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of the water. The liquid temperature of the insolubilizing bath (aqueous boric acid solution) is preferably from 20 ° C to 50 ° C. The insolubilization step is preferably carried out after the production of the laminate, before the dyeing step or the water stretching step.

The crosslinking step is typically carried out by immersing the PVA-based resin layer in an aqueous boric acid solution. Water resistance can be imparted to the PVA-based resin layer by performing the crosslinking treatment. The concentration of the aqueous boric acid solution is preferably from 1 part by weight to 4 parts by weight based on 100 parts by weight of the water. Further, when the crosslinking step is carried out after the above dyeing step, it is preferred to further mix the iodide. By mixing the iodide, the elution of iodine adsorbed to the PVA-based resin layer can be suppressed. The compounding amount of the iodide is preferably from 1 part by weight to 5 parts by weight per 100 parts by weight of the water. Specific examples of iodides are as described above. The liquid temperature of the crosslinking bath (boric acid aqueous solution) is preferably from 20 ° C to 50 ° C. The crosslinking step is preferably extended in the above second boric acid water Implemented before the steps. In a preferred embodiment, the dyeing step, the crosslinking step, and the second boric acid water extending step are carried out in this order.

The polarizer used in the method for producing a polarizing film of the present invention is a low water content polarizer having a water content of 11% by weight or less. However, since the step (1) is applied to the polarizer, even in the step (2), the polarizing is performed. When the surface of the piece is conveyed by the guide roller, the conveyability is still good. The moisture content of the polarizer within 6 hours after drying may be 6% by weight or less and 2% by weight or less. Further, when the water content is too low, there is a problem that the polarizing member is broken during transportation, and therefore the moisture content of the polarizing member is preferably 1% by weight or more. In particular, in the case of the above-mentioned thin polarizer, the present invention is suitable when the water content is 2% by weight or less, and when it is 1 to 1.5% by weight.

The water content of the polarizing member of the present invention can be adjusted by any appropriate method. For example, a method of controlling by adjusting the conditions of the drying step in the manufacturing step of the polarizer can be mentioned.

The moisture content of the polarizer was measured by the following method. That is, the polarizer was cut into a size of 100 × 100 mm, and the initial weight of the sample was measured. Next, the sample was dried at 120 ° C for 2 hours, and the dry weight was measured, and the water content was measured according to the following formula. Water content (% by weight) = {(initial weight - dry weight) / initial weight} x 100. The measurement of the weight was performed three times each, and the average value was used.

The activation treatment can be exemplified by corona treatment, plasma treatment, glow treatment, ozone treatment, and the like. The corona treatment system can be carried out by, for example, a corona treatment machine manufactured by Kasuga Electric Co., Ltd., in a normal-pressure air. The plasma processing system can be discharged by means of a plasma discharge machine manufactured by Sekisui Chemical Co., Ltd. in a normal-pressure air or an inert gas atmosphere such as nitrogen or argon. get on. Glow treatment and ozone treatment can also be carried out according to the usual methods. Among them, corona treatment or plasma treatment is suitable from the viewpoint of equipment cost and processing cost.

The activation treatment is carried out such that the surface roughness (Ra) of the surface of the polarizer reaches 0.6 nm or more. The surface roughness (Ra) is preferably 0.8 nm or more, more preferably 1 nm or more. By setting the surface roughness (Ra) to 0.6 nm or more as described above, even if the water content of the polarizer is 11% by weight or less, and the surface of the polarizer is in contact with the guide roller in the step (2), the polarizer can be made. Good delivery. Further, when the surface roughness (Ra) is too high, the temperature resistance is deteriorated. Therefore, the surface roughness (Ra) is preferably 10 nm or less, and more preferably 5 nm or less.

The measurement of the surface roughness (Ra) is a parameter indicating the surface roughness by arithmetic mean roughness (average value of surface unevenness). The surface roughness (Ra) was measured using an atomic force microscope (AFM) Nanoscope IV manufactured by Veeco Co., Ltd. and measured in a Tapping mode. For the cantilever stent, for example, a Metrology Probe probe: Tap300 (RTESP type) is used. The measurement range was 1 μm square.

In the activation treatment, the treatment conditions are set in accordance with the activation treatment method so that the polarizer reaches the surface roughness (Ra). For example, in the corona treatment, the discharge amount is preferably 250 to 1000 W/m ² /min, preferably 250 to 800 W/m ² /min, more preferably 250 to 600 W/m ² /min, and particularly preferably 250 to 500 W. /m ² /min. The calculation formula of the amount of activation treatment (discharge amount: W/m ² /min) = power (W) / linear velocity (m / min) / electrode length (m). The distance between the electrode and the sample (polarizer) should be 1 mm to 2 mm. The dielectric roller of the activation treatment (corona treatment) is preferably an aluminum roller or a ceramic roller. The grounding roller is preferably a Si roller or a metal roller.

In the method for producing a polarizing film of the present invention, at least one surface of the polarizing member is subjected to an activation treatment in the step (1), but it is also preferable to polarize the light in the case where the double-sided contact roller of the polarizing member contacts the guide roller in the step (2). The double-sided application of the part is activated.

Further, in the method for producing a polarizing film of the present invention, in the step (1), the polarizing member to be subjected to the activation treatment is preferably activated at least on one side, or may be activated as shown in FIG. The other side of the polarizer of the object to be processed is bonded to the transparent protective film via an adhesive layer. Further, in Fig. 1, a transparent protective film T1 is provided on one surface of the polarizer P via the adhesive layer A1, and when the thin polarizer is used as a polarizing member, a resin substrate (amorphous ester-based thermoplastic resin) can be used. Etc.) A thin high-performance polarizing film (polarizer P) that is formed together with a film is used instead.

<Step (2)>

In the step (2), the polarizing member to which the activation treatment has been applied is conveyed while the surface of the activated polarizing member is brought into contact with the guide roller. In the step (2), the surface of the polarizer is transported by contacting the guide roller, but the surface of the polarizer contacting the guide roller is activated in the step (1) to achieve a predetermined surface roughness (Ra), so the transportability good. In Fig. 1, the single-sided protective polarizing film F1 on which the surface of the polarizer P is activated is transported while the activation treatment surface of the polarizer P is in contact with the guide rolls G1 and G2.

<Step (3)>

Next, in step (3), an adhesive is applied to the surface of the polarizer to be formed via the guide roller to form the surface of the adhesive layer and/or the transparent protective film. The face of the aforementioned adhesive layer is formed. In Fig. 1, on the surface of the polarizing member P on which the polarized film F1 is single-sided protected, the adhesive A2 is applied to the coating roller R2 by the coating device D.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various types of water, solvent, hot melt, and radical hardening can be used, and the water system can be used. A suitable agent or a radical hardening type adhesive is preferred. Further, in the one-side protective polarizing film F of Fig. 1, the same adhesive can be used for the adhesive layer A1 in which the transparent protective film T1 and the polarizer P are bonded together.

The water-based adhesive is not particularly limited, and examples thereof include an ethylene polymer system, a gelatin system, a vinyl latex type, a polyurethane resin type, an isocyanate type, a polyester type, and an epoxy type. In such a water-based adhesive, a catalyst such as a crosslinking agent or other additives, an acid, or the like may be mixed as needed. The water-based adhesive is preferably an adhesive containing an ethylene polymer or the like, and an ethylene polymer-based polyvinyl alcohol-based resin is preferred. Further, the polyvinyl alcohol-based resin may contain a water-soluble crosslinking agent such as boric acid or borax, glutaraldehyde or melamine or oxalic acid. In particular, when a polyvinyl alcohol polymer film is used as the polarizer, an adhesive containing a polyvinyl alcohol resin is preferably used from the viewpoint of adhesion. Further, from the viewpoint of improving durability, an adhesive comprising a polyvinyl alcohol-based resin having an ethyl acetate group is preferred.

The polyvinyl alcohol-based resin is not particularly limited, but from the viewpoint of adhesion, the average degree of polymerization is preferably from about 100 to 3,000, and the average degree of saponification is preferably from about 85 to 100 mol%. Further, the concentration of the aqueous solution of the adhesive agent is appropriately determined depending on the thickness of the target adhesive layer, and is not particularly limited. However, it is preferably 0.1 to 15% by weight, more preferably 0.5 to 10% by weight. If the concentration of the solution is too high, the viscosity is too high, and wrinkles and unevenness defects are likely to occur; if the solution concentration is too low, the applicability is deteriorated and unevenness is likely to occur.

The polyvinyl alcohol-based resin may, for example, be a polyvinyl alcohol obtained by saponifying polyvinyl acetate; a derivative thereof; a saponified product of a copolymer of a monomer copolymerizable with vinyl acetate; and a polyvinyl acetal Modified polyvinyl alcohol such as urethanization, urethanization, etherification, grafting, and phosphation. The foregoing single system can be exemplified by (anhydrous) unsaturated carboxylic acid such as maleic acid, fumaric acid, crotonic acid, itaconic acid, (meth)acrylic acid, and esters thereof; α-olefin such as ethylene or propylene, (methyl) Allylsulfonic acid (sodium), sodium sulfonate (monoalkyl maleate), sodium disulfonate maleate, N-methylol acrylamide, acrylamide alkyl sulfonate alkali salt, N-vinylpyrrolidone, N-vinylpyrrolidone derivative, and the like. These polyvinyl alcohol-based resins may be used alone or in combination of two or more.

A polyvinyl alcohol-based resin containing an ethyl acetonitrile group is obtained by reacting a polyvinyl alcohol-based resin with a croproline by a known method. For example, a method in which a polyvinyl alcohol-based resin is dispersed in a solvent such as acetic acid, and a valerene is added thereto; first, a polyvinyl alcohol-based resin is dissolved in dimethylformamide or two A method of adding a valerene or the like to a solvent such as an alkane. Further, a method in which a valerene gas or a liquid valerene is directly contacted with polyvinyl alcohol can be exemplified.

The degree of modification of the ethylenic acid group of the polyvinyl alcohol-based resin containing an ethyl acetate group is not more than 0.1 mol%. If it is less than 0.1 mol%, the water resistance of the adhesive layer will be insufficient, which is not suitable. The degree of modification of the acetamidine group is about 0.1 to 40 mol%, more preferably 1 to 20 mol%, and particularly preferably 2 to 7 mol%. If the degree of modification of the acetamidine group exceeds 40 mol%, The reaction point of the crosslinking agent will be less, and the effect of improving the water resistance will be low. Here, the degree of modification of the ethyl group can be determined using a nuclear magnetic resonance apparatus (NMR: Nuclear Magnetic Resonance).

The crosslinking agent can be used without any particular limitation. For example, when an adhesive of a polyvinyl alcohol-based resin is used as described above, a functional group having at least two reactivity with a polyvinyl alcohol-based resin can be suitably used. compound of. For example, alkyl diamines having an alkylene group and two amine groups such as ethylenediamine, triethylenediamine, hexamethylenediamine, etc.; toluene diisocyanate, toluene hydrogenated diisocyanate, and trishydroxyl Methylpropane diisocyanate toluene adduct, triphenylmethane triisocyanate, methylene bis(4-phenylmethane triisocyanate, isophorone diisocyanate and the like ketone oxime block or phenol embedded Isocyanates such as segments; ethylene glycol diepoxypropyl ether, polyethylene glycol diepoxypropyl ether, glycerol di or triepoxypropyl ether, 1,6-hexanediol diepoxypropyl Epoxy such as triethylolpropane triepoxypropyl ether, diepoxypropyl aniline or diepoxypropylamine; monoaldehydes such as formaldehyde, acetaldehyde, propionaldehyde and butyraldehyde; Dialdehydes such as aldehyde, malondialdehyde, succinaldehyde, glutaraldehyde, maleic acid, and fumaric acid; methylol urea, methylol melamine, alkylated methylol urea, alkyl Amine-formaldehyde resin such as hydroxymethyl melamine, acetamide, benzoamine and formaldehyde condensate; and divalent metal such as sodium, potassium, magnesium, calcium, aluminum, iron, nickel, or trivalent metal Salts thereof in which the oxide and the like, to amine - formaldehyde resins, particularly a compound having a methylol group of methylol appropriate.

The blending amount of the crosslinking agent is usually about 0.1 to 35 parts by weight, and preferably 10 to 25 parts by weight, based on 100 parts by weight of the resin, but in the case of focusing on the durability of the adhesive, in exchange for preparing the adhesive to the preparation. Then the agent layer is It is also effective to mix 30 parts by weight or more and 46 parts by weight or less, preferably 32 parts by weight or more and 40 parts by weight or less, based on the shortening of the time (usable time).

Moreover, an active energy ray-curable adhesive such as an electron beam curing type or an ultraviolet curing type can also be exemplified. In particular, an active energy ray-curing type which is hardenable for a short period of time is preferable, and an ultraviolet-curable adhesive which can be cured at a low energy is preferable.

The ultraviolet curable adhesive can be roughly classified into a radical polymerization hardening type adhesive and a cationic polymerization type adhesive. Further, the radical polymerization hardening type adhesive can be used as a thermosetting type adhesive.

The curable component of the radical polymerization-curable adhesive can be exemplified by a compound having a (meth)acryl fluorenyl group or a compound having a vinyl group. These curable components may be monofunctional or difunctional or more. In addition, these curable components may be used singly or in combination of two or more. As such a curable component, a compound having a (meth) acrylonitrile group is preferable, for example.

The compound having a (meth) acrylonitrile group may, for example, be methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate or (meth) acrylate. Propyl ester, 2-methyl-2-nitropropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, dibutyl methacrylate, (A) Base) butyl acrylate, n-amyl (meth) acrylate, trimeryl (meth) acrylate, 3-pentyl (meth) acrylate, 2,2-dimethyl butyl (methyl) Acrylate, n-hexyl (meth) acrylate, hexadecyl (meth) acrylate, n-octyl (meth) acrylate, 2-ethylhexyl (methyl) propyl A (meth)acrylic acid (carbon number 1-20) alkyl ester such as a olefinic acid ester, 4-methyl-2-propylpentyl (meth) acrylate or n-octadecyl (meth) acrylate.

Further, examples of the compound having a (meth)acryl fluorenyl group include a cycloalkyl (meth)acrylate (for example, cyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate, etc.). Aralkyl acrylate (eg benzyl (meth) acrylate, etc.), polycyclic (meth) acrylate (eg 2-isodecyl (meth) acrylate, 2-norbornylmethyl (A) Acrylate, 5-northene-2-yl-methyl (meth) acrylate, 3-methyl-2-northylmethyl (meth) acrylate, etc.), hydroxyl-containing (A) Acrylates (for example, hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2,3-dihydroxypropylmethyl-butyl (meth)acrylate, etc.), Alkoxy or phenolic (meth) acrylates (2-methoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, 2-methoxy A Oxyethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, ethyl carbitol (meth) acrylate, phenolic ethyl (meth) acrylate, etc.) , epoxy group-containing (meth) acrylates (such as epoxy propyl (meth) acrylate, etc.), halogen-containing (meth) propyl Acid esters (eg 2,2,2-trifluoroethyl (meth) acrylate, 2,2,2-trifluoroethylethyl (meth) acrylate, tetrafluoropropyl (meth) acrylate Ester, hexafluoropropyl (meth) acrylate, octafluoropentyl (meth) acrylate, heptafluorodecyl (meth) acrylate, etc.), alkylaminoalkyl (meth) acrylate (e.g., dimethylaminoethyl (meth) acrylate, etc.), etc.

Further, the compound having a (meth)acryl fluorenyl group other than the above may be exemplified by hydroxyethyl acrylamide, N-methylol acrylamide, and N-methoxymethyl acrylamide (SP value 22.9). ), N-ethoxymethyl acrylamide, (A) A guanamine-containing monomer such as acrylamide or the like. Further, it may, for example, be a nitrogen-containing monomer such as acryloyl ruthenium or the like.

In addition, the curable component of the radical polymerization-type adhesive agent may, for example, be a compound having a plurality of polymerizable double bonds such as a (meth)acryl fluorenyl group or a vinyl group, and the compound may be mixed as a crosslinking component. In the ingredients. Examples of the curable component as the crosslinking component include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, and cyclic trimethylolpropane condensation. Formaldehyde acrylate, two Diol diacrylate, EO-modified diglycerin tetraacrylate, ARONIX M-220 (manufactured by Toagosei Co., Ltd.), LIGHT ACRYLATE 1, 9ND-A (manufactured by Kyoeisha Chemical Co., Ltd.), LIGHT ACRYLATE DGE-4A ( GM ACRYLATE DCP-A (manufactured by Kyoeisha Chemical Co., Ltd.), SR-531 (manufactured by Sartomer Co., Ltd.), CD-536 (manufactured by Sartomer Co., Ltd.), and the like. Further, as needed, for example, various epoxy (meth) acrylates, urethane (meth) acrylates, polyester (meth) acrylates, or various (meth) acrylate monomers may be exemplified. Wait.

The radical polymerization curing type adhesive includes the curable component, and a radical polymerization initiator is added in addition to the above components in addition to the curing method. When the electron beam curing type is used as the above-mentioned adhesive, the above-mentioned adhesive does not necessarily have to contain a radical polymerization initiator, but when an ultraviolet curing type or a thermosetting type is used, a radical polymerization initiator is used. The amount of the radical polymerization initiator to be used is usually from 0.1 to 10 parts by weight, and preferably from 0.5 to 3 parts by weight, per 100 parts by weight of the curable component. Further, in the radical polymerization hardening type adhesive, a carbonyl compound or the like may be added as needed. A light sensitizer that increases the speed and sensitivity of hardening caused by electron beams. The amount of the photosensitizer to be used is usually about 0.001 to 10 parts by weight, and preferably 0.01 to 3 parts by weight, per 100 parts by weight of the curable component.

The curable component of the cationic polymerization hardening type adhesive can be exemplified by a compound having an epoxy group or an oxocycloalkyl group. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various curable epoxy compounds generally known can be used. A suitable epoxy compound is exemplified by a compound having at least two epoxy groups and at least one aromatic ring in the molecule (hereinafter referred to as "aromatic epoxy compound"), or at least two rings in the molecule. At least one of the oxy groups is formed in a compound (hereinafter referred to as "alicyclic epoxy compound") constituting the adjacent two carbon atoms of the alicyclic ring.

<epoxy compound>

The aromatic epoxy compound is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include di-epoxypropyl ether of bisphenol A and diepoxypropyl ether of bisphenol F. And bisphenol type epoxy resins such as diglycidyl ether of bisphenol A; phenolic epoxy resin such as phenol novolac epoxy resin and cresol novolac epoxy resin; and other, biphenyl type epoxy resin Hydroquinone diglycidyl ether, resorcinol diepoxypropyl ether, diepoxypropyl terephthalate, diepoxypropyl phthalate, styrene-butadiene copolymer An epoxide of an epoxide, a styrene-isoprene copolymer, an addition reaction of a terminal carboxylic acid polybutadiene and a bisphenol A type epoxy resin, and the like.

Here, the epoxy resin refers to a compound or a polymer having an average of two or more epoxy groups in the molecule and hardened by the reaction. In this field In the present specification, as long as it has two or more epoxy groups in the curable molecule, even a monomer is called an epoxy resin.

The alicyclic epoxy compound is not particularly limited as long as it does not impair the effects of the present invention, and examples thereof include dicyclopentadiene dioxide, limonene dioxide, and 4-ethylene cyclohexene dioxide. And 3,4-epoxycyclohexylmethyl, 3,4-epoxycyclohexanecarboxylate, and bis(3,4-epoxycyclohexylmethyl)adipate have at least One epoxidized cyclohexyl compound or the like.

In addition to the foregoing, such as 1,6-hexanediol diepoxypropyl ether, trimethylolpropane triepoxypropyl ether, pentaerythritol tetraepoxypropyl ether, and polybutanediol bicyclic ring An aliphatic epoxy compound such as oxypropyl ether; an aromatic ring hydrogenated epoxy compound such as hydrogenated bisphenol A diglycidyl ether; and both ends of a polybutadiene having a hydroxyl group at both ends are epoxy a propyl etherified compound, an internal epoxide of polybutadiene, a partially double bond epoxidized compound of a styrene-butadiene copolymer [for example, "EPOFRIEND" manufactured by Daicel Chemical Industry Co., Ltd." And an epoxy compound such as a polymer-based compound such as an epoxy group-containing compound (for example, "L-207" manufactured by KRATON Co., Ltd.) of an ethylene-butene copolymer and a block copolymer of polyisobutylene, An epoxy compound which can be used as the component (A).

Among these, the aromatic epoxy compound is excellent in durability when the polarizing plate is formed, and is particularly excellent in adhesion to the polarizer and the protective film. In addition, examples of the aromatic epoxy compound include a glycidyl ether of an aromatic compound or a glycidyl ester of an aromatic compound. Specific examples of the epoxy propyl ether of the aromatic compound are, for example, a diepoxypropyl ether such as bisphenol A or a diepoxide of bisphenol F. a bisphenol type epoxy resin such as propyl ether and diglycidyl ether of bisphenol A; a phenolic epoxy resin such as a phenol novolac epoxy resin and a cresol novolac epoxy resin; a biphenyl type epoxy resin; Resin; hydroquinone diepoxypropyl ether; resorcinol diepoxypropyl ether. Further, specific examples of the epoxy propyl ester of the aromatic compound include, for example, diepoxypropyl terephthalate and diepoxypropyl phthalate.

Among them, the epoxy propyl ether of the aromatic compound is particularly excellent in adhesion to the polarizer and the protective film, or durability in the case of forming a polarizing plate. Among the epoxy propyl ethers of the aromatic compound, particularly preferred are, for example, diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and a novolac epoxy resin.

The epoxy compound may be used singly or in combination of two or more. For example, it may be used by mixing two or more kinds of aromatic epoxy compounds, or by mixing an alicyclic epoxy compound mainly with an aromatic epoxy compound.

<oxo compound>

The oxonium compound is not particularly limited as long as it has at least one oxygen-cyclobutane group in the molecule, and any compound which is an acyclic cycloalkyl group can be used. The oxonium compound (B) is exemplified by a compound having one oxygen cyclobutane group in the molecule (hereinafter referred to as "monofunctional oxonium") and two or more oxycyclobutane groups in the molecule. Compound (hereinafter referred to as "polyfunctional oxygen oxime").

As the monofunctional oxime, the following are exemplified: monofunctional oxime containing an alkoxyalkyl group such as 3-ethyl-3-(2-ethylhexyloxymethyl) oxonium, such as 3- Monofunctional aromatic group-containing such as ethyl-3-phenoxymethyloxanthene Oxygen oxime, a hydroxyl group-containing monofunctional oxime such as 3-ethyl-3-hydroxymethyl oxime or the like.

The polyfunctional oxindole may, for example, be 3-ethyl-3-[(3-ethyloxaindole-3-yl)methoxymethyl]oxanium, 1,4-bis[(3-ethyloxy) Indole-3-yl)methoxymethyl]benzene, 1,4-bis[(3-ethyloxaindole-3-yl)methoxy]benzene, 1,3-bis[(3-ethyloxy) Indole-3-yl)methoxy]benzene, 1,2-bis[(3-ethyloxaindole-3-yl)methoxy]benzene, 4,4 ' -bis[(3-ethyloxindole) -3-yl)methoxy]biphenyl, 2,2 ' -bis[(3-ethyloxan-3-yl)methoxy]biphenyl, 3,3 ' ,5,5 ' -tetra Benzyl-4,4 ' -bis[(3-ethyloxaindole-3-yl)methoxy]biphenyl, 2,7-bis[(3-ethyloxaindole-3-yl)methoxy] Naphthalene, bis[4-{(3-ethyloxaindole-3-yl)methoxy}phenyl]methane, bis[2-{(3-ethyloxaindole-3-yl)methoxy}benzene Methyl, 2,2-bis[4-{(3-ethyloxaindole-3-yl)methoxy}phenyl]propane, novolak-type phenol-formaldehyde resin from 3-chloromethyl-3 Etherification modification of ethyl oxonium, 3(4), 8(9)-bis[(3-ethyloxaindole-3-yl)methoxymethyl]-tricyclo[5.2. 1.0 ^2,6 〕decane, 2,3-bis[(3-ethyloxan-3-yl)methoxymethyl]norbornane, 1,1,1-paran [[3-ethyloxy] Indole-3-yl)methoxymethyl]propane, 1-butoxy-2,2-bis[(3-ethyloxy) Indole-3-yl)methoxymethyl]butane, 1,2-bis[{2-(3-ethyloxaindole-3-yl)methoxy}ethylthio]ethane, bis[{ 4-(3-ethyloxaindole-3-yl)methylthio}phenyl]sulfide, 1,6-bis[(3-ethyloxaindole-3-yl)methoxy]-2,2 Hydrolyzed condensate of 3,3,4,4,5,5-octafluorohexane, 3-[(3-ethyloxan-3-yl)methoxy]propyltriethoxydecane, hydrazine A condensate of [(3-ethyloxan-3-yl)methyl]decanoate or the like.

The oxonium compound is preferably a liquid having a molecular weight of 500 or less and a liquid at room temperature from the viewpoints of applicability and adhesion to a protective film when a polarizing plate is formed. Furthermore, from the viewpoint of excellent durability of the polarizing plate, polyfunctional It is particularly suitable for an oxonium or a monofunctional oxime having an intramolecular aromatic ring. As an example of such a particularly suitable oxonium compound, 3-ethyl-3-phenoxymethyloxanium, 3-ethyl-3-[(3-ethyloxan-3-yl) can be exemplified. Methoxymethyl]oxanthene, and 1,4-bis[(3-ethyloxaindole-3-yl)methoxymethyl]benzene.

The oxonium compound may be used alone or in combination of two or more.

<ratio of epoxy compound to oxonium compound>

The ratio of use of the epoxy compound to the oxonium compound is 90/10 to 10/90 by weight. If it is higher or lower than this ratio, the effect of hardening in a short time cannot be fully utilized. The suitable weight ratio of the two is better in terms of coating properties from low viscosity before hardening, and sufficient adhesion and flexibility after hardening, which is about 70/30~20/80, more preferably The weight cutting system is about 60/40~25/75.

<Photocationic polymerization initiator>

The cationic polymerization hardening type adhesive contains the epoxy compound and the oxonium compound described above as a curable component, and since these are all cured by cationic polymerization, a photocationic polymerization initiator is mixed. The photocationic polymerization initiator is produced by irradiation of an active energy ray such as visible light, ultraviolet light, X-ray or electron beam to produce a cationic active species or a Lewis acid, an epoxy group or an oxycyclobutane group. The reaction begins.

By mixing the photocationic polymerization initiator, it is possible to harden at room temperature, and it is necessary to reduce the heat resistance of the polarizer, the distortion caused by expansion or shrinkage, and the like, and the protective film can be well adhered. Further, the photocationic polymerization initiator is acted upon by the irradiation of the active energy ray, so even When it is mixed with an epoxy compound and an oxonium compound, it is still good in terms of storage stability and workability. A compound such as a cationic active species or a Lewis acid is produced by irradiation with an active energy ray, and examples thereof include an arsonium salt such as an aromatic diazo sulfonium salt, an aromatic iodonium salt or an aromatic sulfonium salt, and an iron-heavy olefin. Compounds, etc.

The aromatic diazo hydrazine salt may, for example, be benzodiazepine hexafluoroantimonate, benzodiazepine hexafluorophosphate or benzodiazepine hexafluoroborate.

The aromatic iodonium salt may, for example, be diphenyliodonium (pentafluorophenyl)borate, diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate or di(4-) Nonylphenyl) iodonium hexafluorophosphate and the like.

Examples of the aromatic onium salt include triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium (pentafluorophenyl) borate, and diphenyl [4-(benzene). Thio)phenyl]phosphonium hexafluorophosphate, diphenyl[4-(phenylthio)phenyl]phosphonium hexafluoroantimonate, 4,4 ' -bis(diphenylfluorene)diphenyl sulfide bis hexafluorophosphate, 4,4 '- bis [di ([beta] hydroxyethoxy) phenyl sulfonium] bis diphenyl sulfide hexafluoroantimonate, 4,4' - bis [di ([beta] hydroxy Ethoxy)phenyl hydrazide]diphenyl sulfide bis hexafluorophosphate, 7-[bis(p-tolylmethyl fluorenyl) fluorene]-2-isopropyl 9-oxo sulphide Hexafluoroantimonate, 7-[bis(p-tolylmethylhydrazinyl)phosphonium]-2-isopropyl 9-oxosulfur Tetrakis (pentafluorophenyl) borate, 4-phenylcarbonyl-4 '- diphenyl sulfonium - diphenyl sulfide hexafluorophosphate, 4- (p-tert.butyl-phenyl-carbonyl) -4' - Diphenyl sulfonium-diphenyl sulfide hexafluoroantimonate, 4-(p-tert-butylphenylcarbonyl)-4 ' -di(p-tolylmethyl fluorenyl) fluorene-diphenyl sulfide 五Fluorophenyl) borate and the like.

As the iron-heavy olefin complex, for example, xylene-cyclopentadiene Iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, xylene-cyclopentadienyl iron (II)-gin (trifluoromethylsulfonyl) methane salt Wait.

These photocationic polymerization initiators may be used alone or in combination of two or more. Among them, the aromatic onium salt has ultraviolet light absorption characteristics in a wavelength region of 300 nm or more, and thus has excellent curability, and can provide a cured product having good mechanical strength and adhesion strength, and is particularly suitable for use.

A commercially available product can be easily obtained by a photocationic polymerization initiator, and each of the product names is described, for example, "KAYARAD PCI-220" or "KAYARAD PCI-620" (the above is manufactured by Nippon Kayaku Co., Ltd.). "UVI-6992" (manufactured by The Dow Chemical Company), "ADEKA OPTOMER SP-150", "ADEKA OPTOMER SP-170" (above (made by Adeka)), "CI-5102", "CIT-1370", “CIT-1682”, “CIP-1866S”, “CIP-2048S”, “CIP-2064S” (above is Japanese Soda (share) system), “DPI-101”, “DPI-102”, “DPI-103” ", "DPI-105", "MPI-103", "MPI-105", "BBI-101", "BBI-102", "BBI-103", "BBI-105", "TPS-101", “TPS-102”, “TPS-103”, “TPS-105”, “MDS-103”, “MDS-105”, “DTS-102”, “DTS-103” (above is Green Chemicals Co., Ltd.) ), "PI-2074" (made by Rhodes), "IRGACURE 250", "IRGACURE PAG103", IRGACURE PAG108", IRGACURE PAG121", IRGACURE PAG203" (above), "CPI-100P" , "CPI-101A", "CPI-200K", "CPI-210S" (above is SAN- APRO (manufacturing), etc., especially made by Dow Chemical Co., Ltd. containing diphenyl[4-(phenylthio)phenyl]anthracene as a cationic component "UVI-6992", SAN-APRO (shares) "CPI-100P", "CPI-101A", "CPI-200K", "CPI-210S" are preferred.

The mixing ratio of the photocationic polymerization initiator is in the range of 0.5 to 20% by weight based on the entire cationically polymerizable adhesive. If the ratio is less than 0.5% by weight, the hardening of the adhesive may be insufficient, and the mechanical strength or the subsequent strength may be lowered. On the other hand, if the ratio is more than 20% by weight, the ionic substance in the hardened material is increased, and the hardened material is sucked. The wetness is increased and there is a possibility that the durability can be lowered, so it is not suitable.

Further, the above-mentioned adhesive may contain a metal compound filler. The metal compound filler can be used to control the fluidity of the adhesive layer to stabilize the film thickness, and to obtain a polarizing plate which has a good appearance and is uniform in surface and does not vary in adhesion.

Further, as the adhesive, a dry lamination capable of bonding in a solvent-free or low-solvent state can be used. The dry layering method may be a dry laminating adhesive and a bonding method known in the art, and may be used in accordance with the present invention. Thereby, there is an effect of further reducing streaky unevenness defects and the like.

The dry lamination adhesive can be exemplified by a two-liquid curing type adhesive, a two-liquid solvent type adhesive, a one-liquid solvent-free type adhesive, and the like. An acrylic resin can be used as the two-liquid curing type adhesive; polyester, aromatic polyester, aliphatic polyester, polyester/polyurethane, and polyether/polyurethane can be used. The resin is used as a two-liquid solvent type adhesive; a resin such as a polyether/polyurethane type can be used as a one-liquid solvent-free type adhesive (a type of moisture-curing type).

The above-mentioned adhesive may also contain a suitable additive if necessary. Examples of the additives include a coupling agent such as a decane coupling agent and a titanium coupling agent, a bonding accelerator represented by ethylene oxide, an additive which enhances the wettability to the transparent protective film, and a propylene oxide-based compound. Or hydrocarbon-based (natural, synthetic resin) additives such as improved mechanical strength or processability, ultraviolet absorbers, anti-aging agents, dyes, processing aids, ion trapping agents, antioxidants, adhesion agents, A stabilizer (other than a metal compound filler), a plasticizer, a leveling agent, a foaming inhibitor, an antistatic agent, a heat stabilizer, a stabilizer such as a hydrolysis stabilizer, and the like.

The manner in which the subsequent agent is applied is appropriately selected depending on, for example, the adhesive viscosity or the target thickness. The following are examples of the coating method, such as a reverse coater, a gravure coater (direct, reverse or lithographic), a bar reverse coater, a roll coater, a die coater, and a bar coater. , bar coater, etc. Further, in terms of coating, a method such as a dip coating method can be suitably used.

Further, when the application of the above-mentioned adhesive agent is carried out using a water-based adhesive or the like, it is preferable to carry out the thickness of the finally formed adhesive layer to be 30 to 300 nm. The thickness of the above adhesive layer is more preferably 60 to 250 nm. On the other hand, when a hardening type adhesive is used, it is preferable to carry out the thickness of the said adhesive layer as 0.1-200 micrometer. It is preferably 0.5 to 50 μm, more preferably 0.5 to 10 μm.

<Step (4)>

In the step (4), the polarizer and the transparent protective film are bonded to each other via the above-mentioned adhesive. The bonding of the polarizing member and the transparent protective film can be achieved by A roll laminator or the like is implemented. In FIG. 1, the polarizer P of the one-side protective polarizing film F1 and the transparent protective film T2 are bonded to the adhesive A2 by the laminating rolls R3 and R4 to obtain a double-sided protective polarizing film F2.

<Transparent protective film>

The material constituting the transparent protective film is preferably excellent in transparency, mechanical strength, thermal stability, moisture barrier property, and isotropic properties. For example, a polyester polymer such as polyethylene terephthalate or polyethylene naphthalate, a cellulose polymer such as diethyl cellulose or triacetyl cellulose, or a polymethyl methacrylate An acrylic polymer such as an ester, a styrene polymer such as polystyrene or an acrylonitrile-styrene copolymer (AS resin), or a polycarbonate polymer. Further, the following are examples of the polymer which forms the above transparent protective film: a polyolefin-based polymer such as polyethylene, polypropylene, ring-based or polyolefin having a norbornene structure, an ethylene-propylene copolymer, or chlorine A vinyl polymer, a guanamine polymer such as nylon or an aromatic polyamide, a quinone polymer, a fluorene polymer, a polyether fluorene polymer, a polyether ether ketone polymer, or a poly a phenyl sulfide-based polymer, a vinyl alcohol-based polymer, a vinylidene chloride-based polymer, an ethylene butyral-based polymer, an aryl ester-based polymer, a polyoxymethylene-based polymer, or an epoxy-based polymerization a substance, or a blend of the above polymers, and the like. The transparent protective film may contain one or more optional additives as appropriate. The additive may, for example, be an ultraviolet absorber, an antioxidant, a slip agent, a plasticizer, a release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant or the like. The content of the above thermoplastic resin in the transparent protective film is preferably from 50 to 100% by mass, preferably from 50 to 99% by mass, more preferably from 60 to 98% by mass, particularly preferably from 70 to 97% by mass. If the above transparent protective film When the content of the thermoplastic resin is 50% by mass or less, there is a fear that the thermoplastic resin cannot sufficiently exhibit the high transparency and the like of itself.

The thickness of the transparent protective film can be appropriately set, and it is usually about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. It is preferably 1 to 300 μm, preferably 5 to 200 μm.

Further, when a transparent protective film is provided on both surfaces of the polarizing member, a protective film made of the same polymer material may be used for the surface, and a transparent protective film made of a dissimilar polymer material or the like may be used. For example, as shown in FIG. 1, when the step (1) to the step (4) are applied to the one-side protective polarizing film F1 to manufacture the double-sided protective polarizing film F2, the transparent protective film T1 of the one-side protective polarizing film F1 is preferably from the fiber. A polymer (triacetate or the like), a polyolefin having a norbornene structure, an acrylic polymer, a polyester polymer, and a polyolefin polymer (polypropylene or the like) are appropriately selected and used. In this case, the transparent protective film T2 is preferably a cellulose-based polymer (such as cellulose triacetate), a polyolefin having a norbornene structure, an acrylic polymer, a polyester polymer, or a polyolefin polymer ( It is suitably selected and used in polypropylene or the like.

After the aforementioned bonding step, an adhesive layer is formed. The formation of the subsequent layer is carried out depending on the kind of the adhesive. Further, in the case of a water-based adhesive, an adhesive layer may be formed in the step (3) and bonded in the step (4).

When the adhesive is a water-based adhesive or a solvent-based adhesive, a drying step is applied after the bonding step to form an adhesive layer. When a water-based adhesive is used, the drying step is preferably carried out at a drying temperature of about 20 to 80 ° C, preferably about 40 to 80 ° C for about 1 to 10 minutes, preferably 1 to 5 minutes.

When the adhesive is a radical curing adhesive, after the bonding step, a hardening step is applied to form an adhesive layer. The radical-curable adhesive is subjected to a respective hardening treatment, and is subjected to electron beam irradiation for the electron beam curing type, ultraviolet treatment for the ultraviolet curing type, and heat treatment for the heat curing type. These hardening treatments are set in accordance with the type of hardening, the type of the adhesive, and the thickness of the adhesive layer.

Further, the method for producing a polarizing film of the present invention has the aforementioned steps (1) to (4), and may include other steps than the above steps.

For example, an easy adhesion layer may be provided between the transparent protective film and the adhesive layer when the polarizer is bonded to the transparent protective film. The easy-adhesive layer may be, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a polyoxane system, a polyamine skeleton, a polyimine skeleton, a polyvinyl alcohol skeleton, or the like. Formed by a resin. These polymer resins may be used singly or in combination of two or more. Further, other additives may be added to the formation of the easy-to-adhere layer. Specifically, a stabilizer such as an adhesive agent, an ultraviolet absorber, an antioxidant, or a heat stabilizer can be further used.

The easy-adhesive layer is usually provided on the transparent protective film in advance, so that the easy-adhesive layer side of the transparent protective film and the polarizer pass through the adhesive layer. The formation of the easy-adhesion layer is carried out by coating and drying the formation of the easy-adhesion layer on a transparent protective film by a conventional technique. The forming material of the easy-adhesion layer is usually prepared into a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the layer which is easily dried is preferably from 0.01 to 5 μm, preferably from 0.02 to 2 μm, more preferably from 0.05 to 1 μm. In addition, easy The layer may be provided in multiple layers, but it is preferable to make the total thickness of the easy-to-adhere layer in the above range.

When the polarizing film of the present invention is produced in a continuous production line, the linear velocity is preferably from 1 to 500 m/min, preferably from 5 to 300 m/min, more preferably from 10 to 100 m/min, depending on the hardening time of the adhesive. If the line speed is too small, the productivity is insufficient, or the damage to the transparent protective film is too large, and a polarizing film capable of withstanding durability tests or the like cannot be produced. If the line speed is too large, the hardening of the adhesive will be insufficient, and the target adhesion may not be obtained.

A polarizing film having a transparent protective film on one side or both sides of the polarizing member is obtained in the above manner, and a hard layer, an anti-reflective layer, and an anti-adhesive layer may be disposed on a surface of the transparent protective film on which the polarizing member is not attached. Functional layers such as diffusion layers and anti-glare layers. Further, the functional layer such as the hard layer, the antireflection layer, the anti-adhesion layer, the diffusion layer or the anti-glare layer may be provided separately from the transparent protective film itself, and may be separately provided as an individual from the transparent protective film.

The polarizing film of the present invention can be used as an optical film by laminating with other optical layers in practical use. The optical layer is not particularly limited, and for example, one or two or more reflective sheets or semi-transmissive sheets, phase difference plates (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, and the like can be used. An optical layer used to form a liquid crystal display device or the like. In particular, it is preferable to use a reflective polarizing film or a semi-transmissive polarizing film in which a reflecting plate or a semi-transmissive reflecting plate is laminated on the polarizing film of the present invention, and an elliptically polarized light obtained by laminating a phase difference plate on the polarizing film. a film or a circularly polarizing film, a wide viewing angle polarizing film formed by laminating a viewing angle compensation film on a polarizing film, or a polarizing film A polarizing film formed by laminating a brightness enhancement film on the film.

The optical film in which the optical layer is laminated on the polarizing film may be formed by sequentially laminating in a manufacturing process such as a liquid crystal display device, but the film may be laminated to form an optical film to have quality stability or assembly work. It is excellent in that the manufacturing steps of the liquid crystal display device and the like can be improved. The laminate system may use an appropriate bonding means such as an adhesive layer. When the polarizing film or other optical film described above is subsequently used, the optical axis thereof may be set to an appropriate arrangement angle in accordance with the target phase difference characteristic or the like.

The polarizing film described above or an optical film in which at least one layer of the polarizing film is laminated may be provided with an adhesive layer for use in connection with another member such as a liquid crystal cell. The adhesive for forming the adhesive layer is not particularly limited, and may be appropriately selected and used, for example, an acrylic polymer, a polyoxymethylene polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine or a rubber. A polymer such as a base polymer. In particular, it is possible to suitably use, for example, an acrylic pressure-sensitive adhesive which is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesion properties, and is excellent in weather resistance and heat resistance.

The adhesive layer may be an overlapping layer of different compositions or types, and may be provided on one or both sides of a polarizing film or an optical film. Further, in the case of double-sided mounting, an adhesive layer having a different composition, type, thickness, or the like can be formed in a surface such as a polarizing film or an optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use or the adhesion, and is usually 1 to 500 μm, preferably 1 to 200 μm, particularly preferably 1 to 100 μm.

The exposed surface of the adhesive layer is temporarily covered with a release film for the purpose of preventing contamination or the like before being used for practical use. In this way, it can be prevented Contact with the adhesive layer in the normal processing state. As the release film, in addition to the above thickness conditions, a suitable sheet material such as a plastic film, a resin sheet, paper, cloth, non-woven fabric, mesh, foamed sheet or metal foil, or the like may be used. It is conventionally appropriate to use a suitable release agent such as a polyoxyalkylene or a long-chain alkyl group, a fluorine-based or a molybdenum sulfide as a coating treatment.

The polarizing film or the optical film of the present invention can be suitably used for formation of various devices such as a liquid crystal display device. The formation of the liquid crystal display device can be carried out in accordance with a conventional method. In other words, the liquid crystal display device is usually formed by appropriately assembling a liquid crystal cell, a polarizing film, an optical film, and an optional illumination system, and a combination of a driving circuit and the like. In the present invention, in addition to using the polarizing light of the present invention. The film or the optical film is not particularly limited except for this point, and can be obtained by a conventional method. For the liquid crystal cell, any type such as TN type, STN type, or π type can also be used.

A liquid crystal display device such as a liquid crystal display device in which a polarizing film or an optical film is disposed on one side or both sides of the liquid crystal cell, or a liquid crystal display device such as a backlight or a reflector used in the illumination system can be formed. At this time, the polarizing film or the optical film according to the present invention may be disposed on one side or both sides of the liquid crystal cell. When a polarizing film or an optical film is provided on both sides, the same may be the same or different. Further, when the liquid crystal display device is formed, an appropriate member such as a diffusion plate, an anti-glare layer, an anti-reflection film, a protective plate, a ruthenium array, a lens array sheet, a light diffusion plate, or a backlight can be disposed at a suitable position in one layer. Or 2 or more layers.

Example

Hereinafter, the present invention will be specifically described by examples, but the present invention is not limited by the examples. In addition, "parts" and "%" in each example are based on weight.

Make a protective polarizing film.

<Production of Sheet Protected Polarizing Film (1)>

In order to produce a thin polarizing film, first, a laminate having a 9 μm-thick PVA layer formed on an amorphous PET substrate is subjected to an air-assisted extension at an elongation temperature of 130 ° C to form an extended laminate; and then, by extending the laminate The colored layered body was formed by dyeing the body; the colored layered body was further extended with the amorphous PET substrate through a boric acid water having an extension temperature of 65 degrees to have a total stretching ratio of 5.94 times, and dried at 50 ° C for 4 minutes. An optical film laminate having a PVA layer of 4 μm thick was formed. By such two-stage extension, an optical film laminate comprising a PVA layer having a thickness of 4 μm, which constitutes a PVA molecule of a PVA layer formed on a non-crystalline PET substrate, is highly oriented and dyed. The adsorbed iodine is a high-performance polarizing film that is highly oriented in the same direction as a polyiodide complex. Next, a polyvinyl alcohol-based adhesive is applied to the surface of the polarizing film of the optical film laminate, and a saponified 40 μm-thick cellulose triacetate film (transparent protective film) is bonded thereto, and then amorphous PET is attached. The substrate is peeled off. It is called a thin sheet-protected polarizing film (1). The polarizing film (polarizing member) of the sheet-protecting polarizing film (1) had a water content of 1.8%.

<Production of Sheet Protected Polarizing Film (2)>

Between the rolls having different speed ratios, the polyvinyl alcohol film having a thickness of 80 μm was stretched to 3 times while being dyed in an iodine solution at 30° C. and a 0.3% concentration for 1 minute. Thereafter, at 60 ° C and containing 4% concentration of boric acid and 10% concentration of potassium iodide The aqueous solution was immersed for 0.5 minutes while extending to a total stretching ratio of 6 times. Subsequently, the mixture was immersed in an aqueous solution containing potassium iodide at a concentration of 1.5% at 30 ° C for 10 seconds, and then dried at 50 ° C for 4 minutes to obtain a polarizer having a thickness of 20 μm. A saponified cellulose triacetate film (transparent protective film) having a thickness of 40 μm was applied to both surfaces of the polarizer through a polyvinyl alcohol-based adhesive to form a polarizing film. Hereinafter, it is referred to as a sheet-protecting polarizing film (2). The polarizing film (polarizing member) of the sheet-protecting polarizing film (2) had a water content of 11%.

<Transparent protective film>

A decene-based film (ZEONOR film, manufactured by Japan ZEON Co., Ltd.) having a thickness of 60 μm was used for corona treatment.

(Adjustment of active energy ray-curable adhesive)

Each of the following components was mixed in a ratio of HEAA: 50 parts, ACMO: 50 parts, IRGACURE 819: 3 parts, and stirred at 50 ° C for 1 hour to obtain an active energy ray-curable adhesive.

HEAA (hydroxyethyl acrylamide), manufactured by Xingren Company

ACMO (acrylic thiophene), manufactured by Xingren Company

IRGACURE 819 (bis(2,4,6-trimethylbenzylidene)-phenylphosphine oxide, Ciba. Made by Japan

Example 1

(step 1)

The side of the transparent protective film of the sheet protective polarizing film (1) is the side of the processing roll, and according to the aspect of Fig. 1, the conveying sheet protects the polarizing film (1). The activation treatment was carried out by corona treatment using a corona irradiation machine (CT-0212, manufactured by Kasuga Electric Co., Ltd.) on one surface of the polarizing member at a discharge amount of 250 W/m ² /min. The surface roughness (Ra) of the surface of the polarizing member which was activated was 0.62 nm.

(Step 2)

Next, the polarizing film (1) is protected by the activated sheet on the surface of the polarizer, and the side of the polarizer is used as the guide roller side. According to the aspect of Fig. 1, the sheet protects the polarizing film (1).

(Step 3)

Next, the above-mentioned adhesive (active energy ray-curable adhesive) was applied to the polarizer surface of the sheet-protecting polarizing film (1) using a micro gravure coater.

(Step 4)

Next, after the application of the above-mentioned adhesive agent, the transparent protective film is bonded by a roll press through the above-mentioned adhesive. Ultraviolet rays were irradiated from the side of the transparent protective film to obtain a polarizing film having a transparent protective film on both sides. It is bonded at a line speed of 20 m/min.

Examples 2 to 3 and Comparative Examples 1 to 4

In the first embodiment, the type of the sheet-protecting polarizing film and the amount of corona discharge treatment for the polarizer were changed as shown in Table 1, and a polarizing film was produced in the same manner as in Example 1. In addition, the moisture content of the sheet protective polarizing film is controlled by the drying temperature.

〔Evaluation〕

The polarizing films obtained in the examples and the comparative examples were subjected to the following evaluations. The results are shown in Table 1.

<Transportability>

The transportability of the step (2) was evaluated on the basis of the following criteria.

○: Slidability was good, and no wrinkles, scratches, and the like occurred during transportation.

×: The clamping force with the roller was too high, and the film was wrinkled, scratched, or poorly laminated.

P‧‧‧ polarizer

T1, T2‧‧‧ transparent protective film

A1, A2‧‧‧ adhesive

F1‧‧‧Single-sided protective polarizing film

F2‧‧‧Double-sided protective polarizing film

C‧‧‧Activation treatment device

D‧‧‧ Coating device

R1‧‧‧Processing roller

R2‧‧‧ coating roller

R3, R4‧‧‧ laminating rolls

G1, G2‧‧‧ guide roller

Claims (5)

A method for producing a polarizing film, wherein the polarizing film is provided with a transparent protective film on at least one side of the polarizing member via an adhesive layer, and the method for manufacturing the polarizing film is characterized by the following steps: Step (1): An activation treatment is applied to at least one surface of the polarizer having a water content of 11% by weight or less to have a surface roughness (Ra) of 0.6 nm or more on the surface of the polarizer; and Step (2): polarizing the above-described activated treatment The member is transported while contacting the surface of the actuated polarizer with the guide roller; and step (3): applying an adhesive to the surface of the polarizer that is transported via the guide roller to form the adhesive layer, and/ Or a surface of the transparent protective film forming the adhesive layer; and a step (4) of bonding the polarizer and the transparent protective film via the adhesive. The method for producing a polarizing film according to claim 1, wherein the polarizing member has a thickness of 10 μm or less. The method for producing a polarizing film according to claim 1 or 2, wherein the polarizing member is a continuous strip-shaped polarizing film composed of a polyvinyl alcohol-based resin having a dichroic substance oriented, and is assisted by air-assisted stretching and boric acid. The two-stage extension step of extending the water is carried out by extending a laminate including a polyvinyl alcohol-based resin layer formed on the thermoplastic resin substrate. The method for producing a polarizing film according to claim 1 or 2, wherein said activating said The treatment is corona treatment or plasma treatment. The method for producing a polarizing film according to claim 1 or 2, wherein the activating treatment is corona treatment, and the discharge amount during corona treatment is 250 to 1000 W/m ² /min.